// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <stdint.h>

#include <memory>
#include <utility>

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/files/file.h"
#include "base/files/file_util.h"
#include "base/files/scoped_temp_dir.h"
#include "base/location.h"
#include "base/macros.h"
#include "base/run_loop.h"
#include "base/single_thread_task_runner.h"
#include "base/threading/thread_task_runner_handle.h"
#include "storage/browser/fileapi/quota/open_file_handle.h"
#include "storage/browser/fileapi/quota/quota_reservation.h"
#include "storage/browser/fileapi/quota/quota_reservation_manager.h"
#include "testing/gtest/include/gtest/gtest.h"

using storage::kFileSystemTypeTemporary;
using storage::OpenFileHandle;
using storage::QuotaReservation;
using storage::QuotaReservationManager;

namespace content {

namespace {

    const char kOrigin[] = "http://example.com";
    const storage::FileSystemType kType = kFileSystemTypeTemporary;
    const int64_t kInitialFileSize = 1;

    typedef QuotaReservationManager::ReserveQuotaCallback ReserveQuotaCallback;

    int64_t GetFileSize(const base::FilePath& path)
    {
        int64_t size = 0;
        base::GetFileSize(path, &size);
        return size;
    }

    void SetFileSize(const base::FilePath& path, int64_t size)
    {
        base::File file(path, base::File::FLAG_OPEN_ALWAYS | base::File::FLAG_WRITE);
        ASSERT_TRUE(file.IsValid());
        ASSERT_TRUE(file.SetLength(size));
    }

    class FakeBackend : public QuotaReservationManager::QuotaBackend {
    public:
        FakeBackend()
            : on_memory_usage_(kInitialFileSize)
            , on_disk_usage_(kInitialFileSize)
        {
        }
        ~FakeBackend() override { }

        void ReserveQuota(const GURL& origin,
            storage::FileSystemType type,
            int64_t delta,
            const ReserveQuotaCallback& callback) override
        {
            EXPECT_EQ(GURL(kOrigin), origin);
            EXPECT_EQ(kType, type);
            on_memory_usage_ += delta;
            base::ThreadTaskRunnerHandle::Get()->PostTask(
                FROM_HERE,
                base::Bind(base::IgnoreResult(callback), base::File::FILE_OK, delta));
        }

        void ReleaseReservedQuota(const GURL& origin,
            storage::FileSystemType type,
            int64_t size) override
        {
            EXPECT_LE(0, size);
            EXPECT_EQ(GURL(kOrigin), origin);
            EXPECT_EQ(kType, type);
            on_memory_usage_ -= size;
        }

        void CommitQuotaUsage(const GURL& origin,
            storage::FileSystemType type,
            int64_t delta) override
        {
            EXPECT_EQ(GURL(kOrigin), origin);
            EXPECT_EQ(kType, type);
            on_disk_usage_ += delta;
            on_memory_usage_ += delta;
        }

        void IncrementDirtyCount(const GURL& origin,
            storage::FileSystemType type) override { }
        void DecrementDirtyCount(const GURL& origin,
            storage::FileSystemType type) override { }

        int64_t on_memory_usage() { return on_memory_usage_; }
        int64_t on_disk_usage() { return on_disk_usage_; }

    private:
        int64_t on_memory_usage_;
        int64_t on_disk_usage_;

        DISALLOW_COPY_AND_ASSIGN(FakeBackend);
    };

    class FakeWriter {
    public:
        explicit FakeWriter(std::unique_ptr<OpenFileHandle> handle)
            : handle_(std::move(handle))
            , path_(handle_->platform_path())
            , max_written_offset_(handle_->GetEstimatedFileSize())
            , append_mode_write_amount_(0)
            , dirty_(false)
        {
        }

        ~FakeWriter()
        {
            if (handle_)
                EXPECT_FALSE(dirty_);
        }

        int64_t Truncate(int64_t length)
        {
            int64_t consumed = 0;

            if (max_written_offset_ < length) {
                consumed = length - max_written_offset_;
                max_written_offset_ = length;
            }
            SetFileSize(path_, length);
            return consumed;
        }

        int64_t Write(int64_t max_offset)
        {
            dirty_ = true;

            int64_t consumed = 0;
            if (max_written_offset_ < max_offset) {
                consumed = max_offset - max_written_offset_;
                max_written_offset_ = max_offset;
            }
            if (GetFileSize(path_) < max_offset)
                SetFileSize(path_, max_offset);
            return consumed;
        }

        int64_t Append(int64_t amount)
        {
            dirty_ = true;
            append_mode_write_amount_ += amount;
            SetFileSize(path_, GetFileSize(path_) + amount);
            return amount;
        }

        void ReportUsage()
        {
            handle_->UpdateMaxWrittenOffset(max_written_offset_);
            handle_->AddAppendModeWriteAmount(append_mode_write_amount_);
            max_written_offset_ = handle_->GetEstimatedFileSize();
            append_mode_write_amount_ = 0;
            dirty_ = false;
        }

        void ClearWithoutUsageReport()
        {
            handle_.reset();
        }

    private:
        std::unique_ptr<OpenFileHandle> handle_;
        base::FilePath path_;
        int64_t max_written_offset_;
        int64_t append_mode_write_amount_;
        bool dirty_;
    };

    void ExpectSuccess(bool* done, base::File::Error error)
    {
        EXPECT_FALSE(*done);
        *done = true;
        EXPECT_EQ(base::File::FILE_OK, error);
    }

    void RefreshReservation(QuotaReservation* reservation, int64_t size)
    {
        DCHECK(reservation);

        bool done = false;
        reservation->RefreshReservation(size, base::Bind(&ExpectSuccess, &done));
        base::RunLoop().RunUntilIdle();
        EXPECT_TRUE(done);
    }

} // namespace

class QuotaReservationManagerTest : public testing::Test {
public:
    QuotaReservationManagerTest() { }
    ~QuotaReservationManagerTest() override { }

    void SetUp() override
    {
        ASSERT_TRUE(work_dir_.CreateUniqueTempDir());
        file_path_ = work_dir_.GetPath().Append(FILE_PATH_LITERAL("hoge"));
        SetFileSize(file_path_, kInitialFileSize);

        std::unique_ptr<QuotaReservationManager::QuotaBackend> backend(
            new FakeBackend);
        reservation_manager_.reset(new QuotaReservationManager(std::move(backend)));
    }

    void TearDown() override { reservation_manager_.reset(); }

    FakeBackend* fake_backend()
    {
        return static_cast<FakeBackend*>(reservation_manager_->backend_.get());
    }

    QuotaReservationManager* reservation_manager()
    {
        return reservation_manager_.get();
    }

    const base::FilePath& file_path() const
    {
        return file_path_;
    }

private:
    base::MessageLoop message_loop_;
    base::ScopedTempDir work_dir_;
    base::FilePath file_path_;
    std::unique_ptr<QuotaReservationManager> reservation_manager_;

    DISALLOW_COPY_AND_ASSIGN(QuotaReservationManagerTest);
};

TEST_F(QuotaReservationManagerTest, BasicTest)
{
    scoped_refptr<QuotaReservation> reservation = reservation_manager()->CreateReservation(GURL(kOrigin), kType);

    {
        RefreshReservation(reservation.get(), 10 + 20 + 3);
        int64_t cached_reserved_quota = reservation->remaining_quota();
        FakeWriter writer(reservation->GetOpenFileHandle(file_path()));

        cached_reserved_quota -= writer.Write(kInitialFileSize + 10);
        EXPECT_LE(0, cached_reserved_quota);
        cached_reserved_quota -= writer.Append(20);
        EXPECT_LE(0, cached_reserved_quota);

        writer.ReportUsage();
    }

    EXPECT_EQ(3, reservation->remaining_quota());
    EXPECT_EQ(kInitialFileSize + 10 + 20, GetFileSize(file_path()));
    EXPECT_EQ(kInitialFileSize + 10 + 20, fake_backend()->on_disk_usage());
    EXPECT_EQ(kInitialFileSize + 10 + 20 + 3, fake_backend()->on_memory_usage());

    {
        RefreshReservation(reservation.get(), 5);
        FakeWriter writer(reservation->GetOpenFileHandle(file_path()));

        EXPECT_EQ(0, writer.Truncate(3));

        writer.ReportUsage();
    }

    EXPECT_EQ(5, reservation->remaining_quota());
    EXPECT_EQ(3, GetFileSize(file_path()));
    EXPECT_EQ(3, fake_backend()->on_disk_usage());
    EXPECT_EQ(3 + 5, fake_backend()->on_memory_usage());

    reservation = NULL;

    EXPECT_EQ(3, fake_backend()->on_memory_usage());
}

TEST_F(QuotaReservationManagerTest, MultipleWriter)
{
    scoped_refptr<QuotaReservation> reservation = reservation_manager()->CreateReservation(GURL(kOrigin), kType);

    {
        RefreshReservation(reservation.get(), 10 + 20 + 30 + 40 + 5);
        int64_t cached_reserved_quota = reservation->remaining_quota();
        FakeWriter writer1(reservation->GetOpenFileHandle(file_path()));
        FakeWriter writer2(reservation->GetOpenFileHandle(file_path()));
        FakeWriter writer3(reservation->GetOpenFileHandle(file_path()));

        cached_reserved_quota -= writer1.Write(kInitialFileSize + 10);
        EXPECT_LE(0, cached_reserved_quota);
        cached_reserved_quota -= writer2.Write(kInitialFileSize + 20);
        cached_reserved_quota -= writer3.Append(30);
        EXPECT_LE(0, cached_reserved_quota);
        cached_reserved_quota -= writer3.Append(40);
        EXPECT_LE(0, cached_reserved_quota);

        writer1.ReportUsage();
        writer2.ReportUsage();
        writer3.ReportUsage();
    }

    EXPECT_EQ(kInitialFileSize + 20 + 30 + 40, GetFileSize(file_path()));
    EXPECT_EQ(kInitialFileSize + 10 + 20 + 30 + 40 + 5,
        fake_backend()->on_memory_usage());
    EXPECT_EQ(kInitialFileSize + 20 + 30 + 40, fake_backend()->on_disk_usage());

    reservation = NULL;

    EXPECT_EQ(kInitialFileSize + 20 + 30 + 40, fake_backend()->on_disk_usage());
}

TEST_F(QuotaReservationManagerTest, MultipleClient)
{
    scoped_refptr<QuotaReservation> reservation1 = reservation_manager()->CreateReservation(GURL(kOrigin), kType);
    RefreshReservation(reservation1.get(), 10);
    int64_t cached_reserved_quota1 = reservation1->remaining_quota();

    scoped_refptr<QuotaReservation> reservation2 = reservation_manager()->CreateReservation(GURL(kOrigin), kType);
    RefreshReservation(reservation2.get(), 20);
    int64_t cached_reserved_quota2 = reservation2->remaining_quota();

    std::unique_ptr<FakeWriter> writer1(
        new FakeWriter(reservation1->GetOpenFileHandle(file_path())));

    std::unique_ptr<FakeWriter> writer2(
        new FakeWriter(reservation2->GetOpenFileHandle(file_path())));

    cached_reserved_quota1 -= writer1->Write(kInitialFileSize + 10);
    EXPECT_LE(0, cached_reserved_quota1);

    cached_reserved_quota2 -= writer2->Append(20);
    EXPECT_LE(0, cached_reserved_quota2);

    writer1->ReportUsage();
    RefreshReservation(reservation1.get(), 2);
    cached_reserved_quota1 = reservation1->remaining_quota();

    writer2->ReportUsage();
    RefreshReservation(reservation2.get(), 3);
    cached_reserved_quota2 = reservation2->remaining_quota();

    writer1.reset();
    writer2.reset();

    EXPECT_EQ(kInitialFileSize + 10 + 20, GetFileSize(file_path()));
    EXPECT_EQ(kInitialFileSize + 10 + 20 + 2 + 3,
        fake_backend()->on_memory_usage());
    EXPECT_EQ(kInitialFileSize + 10 + 20, fake_backend()->on_disk_usage());

    reservation1 = NULL;
    EXPECT_EQ(kInitialFileSize + 10 + 20 + 3, fake_backend()->on_memory_usage());

    reservation2 = NULL;
    EXPECT_EQ(kInitialFileSize + 10 + 20, fake_backend()->on_memory_usage());
}

TEST_F(QuotaReservationManagerTest, ClientCrash)
{
    scoped_refptr<QuotaReservation> reservation1 = reservation_manager()->CreateReservation(GURL(kOrigin), kType);
    RefreshReservation(reservation1.get(), 15);

    scoped_refptr<QuotaReservation> reservation2 = reservation_manager()->CreateReservation(GURL(kOrigin), kType);
    RefreshReservation(reservation2.get(), 20);

    {
        FakeWriter writer(reservation1->GetOpenFileHandle(file_path()));

        writer.Write(kInitialFileSize + 10);

        reservation1->OnClientCrash();
        writer.ClearWithoutUsageReport();
    }
    reservation1 = NULL;

    EXPECT_EQ(kInitialFileSize + 10, GetFileSize(file_path()));
    EXPECT_EQ(kInitialFileSize + 15 + 20, fake_backend()->on_memory_usage());
    EXPECT_EQ(kInitialFileSize + 10, fake_backend()->on_disk_usage());

    reservation2 = NULL;
    EXPECT_EQ(kInitialFileSize + 10, fake_backend()->on_memory_usage());
}

} // namespace content
